Hello @ajinananth
This domain bitzburg.com does not have valid DKIM keys or none. Kindly create them for the domain by either creating a website or creating them manually
https://community.cyberpanel.net/t/how-to-manually-set-up-spf-dkim-and-dmarc-inside-cyberpanel/30666#installing-and-setting-up-opendkim-4